<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Title</title>
  <style>
    div{
      width: 100px;
      height: 100px;
      border: 1px solid red
    }
    #d1{
      /*margin-top: 100px;*/
      /*margin-bottom: 200px;*/
      /*margin-left: 100px;*/
      /*四个方向100*/
      /*margin: 100px;*/
      /*设置上下100 左右200*/
      /*margin: 100px 200px;*/
      /*块级元素自身设置行内居中
      text-align:center;让元素内容居中*/
      /*margin: 0 auto;*/
      /*上右下左顺时针赋值*/
      /*margin: 10px 20px 30px 40px;*/
      margin-bottom: 50px;
    }
    #d2{
      margin-top: 100px;
    }
    #s1{
      /*行内元素上下外边距无效*/
        margin-right: 100px;
    }
    #s2{
        /*左右相邻两个元素彼此添加外边距,求和*/
        margin-left: 50px;
    }
  </style>
</head>
<body>
<span id="s1">span1</span><span id="s2">span2</span>
<div id="d1">div1</div>
<div id="d2">div2</div>
</body>
</html>